Question

Two rays travelling parallel to the principal axis

strike a large plano-convex lens of a refractive index of 1.60. If the convex face is spherical, a ray near the edge does not pass through the focal point (spherical aberration occurs). If this face has a radius of curvature of 20.0 cm and the two rays are at h₁ = 0.50 cm and h₂ = 12.0 cm from the principal axis, then find the difference in the positions where they cross the principal axis.

Answer 1

Snell’s law at spherical surface for the first ray 

µ sin i₁ = sin r₁